Triaxial induction tool with electrode sleeve: A study of its response to borehole eccentricity

Abstract

We developed a finite difference (FD) code to model the response of a multiple-spacing triaxial array induction tool with a multiple-electrode type sleeve in a homogeneous medium and decentralized within a borehole in a homogeneous medium. The electrode sleeve reduces the response of the transverse couplings to eccentering in a conductive borehole. The model response was carefully checked for grid refinement, while attempting to minimize run time. Many details of the electrode sleeve geometry were studied, using this code, which led to the final electrode sleeve design. The comparison between the FD code and two other independent codes is quantitative. Good agreement is found between measurements and calculations.